In making cheese, the product is typically first fabricated into blocks, such as cubes weighing about 640 pounds. Such 640 pound blocks are then processed through various cutting steps to make retail-size chunks. The focus of this invention is the process of breaking the large block down into the retail-size chunks.
In conventional processing, the e.g. 640 pound block of cheese is first passed through a block cutting harp having cutting wires oriented horizontally so as to cut the block into a stack of horizontally disposed slabs, stacked on top of each other. Such large blocks of cheese are pushed along a first conveyor through the block cutting harp by a block pusher having horizontally extending slots at respective elevations occupied by the cutting wires, such that the pusher block can be pushed part-way through the cutting harp, thus to push the entire length of the cheese block through the cutting harp. As illustrated in FIG. 1, multiple blocks of cheese can be pushed through the harp in serial order by a single push of the pusher whereupon the pusher is retracted to make room for placing additional blocks of cheese between the pusher and the harp.
After the block is cut into slabs, the next step is to separate the individual slabs from the stack of slabs which were cut from the block. In conventional practice, a respective slab is picked up from the block, and placed on a second conveyor leading to a second, slab-cutting harp. The second, slab-cutting harp has vertically oriented cutting wires for making vertical cuts along the length of the slab. A slab pusher much like the block pusher shown in FIG. 1, but optionally of lesser height, pushes the slab through the harp, then is retracted so a subsequent slab can be placed on the second, slab conveyor.
As the second pusher pushes the slab through the second harp, the harp cuts the cheese slab into a series of parallel elongate ribbons of cheese, each extending the full length of the slab. The slab is then passed to a third conveyor typically oriented 90 degrees to the second conveyor, whereby the ribbons of the slab are oriented transverse to the length of the conveyor. The slab is then pushed along the third conveyor by a third pusher through a third harp having vertically oriented cutting wires spaced across the width of the third conveyor, thus to cut the respective ribbons of cheese into shorter lengths for individual retail packaging.
After passing through the third harp, the cheese slab bears both longitudinal and transverse vertical cuts cutting the slab into respective chunks of cheese, sized e.g. for retail sale. Such chunks may be, for example and without limitation, as small as 4 ounces up to as great as 10 pounds per chunk.
While the slab has thus been cut into individual chunks, the respective individual chunks typically stick together, such that the chunks are not discrete pieces, but rather, are susceptible to being broken apart by manual handling and manipulation. While such manual breaking apart of an individual pair of chunks is not physically strenuous work, repeated such tasks result in accumulated excess stress on the hands and wrists of the workers who perform such tasks over the course of a work day. In particular, workers who perform such tasks for extended periods of time may be prone to develop carpal tunnel difficulties, or related repetitious work malady.
In addition, the labor cost of such manual breaking apart of the individual chunks of cheese adds significantly to the routine cost of making cheese.
Thus, in order to overcome such worker injury risks, and to reduce the cost of such labor, it is an object of the invention to provide apparatus for cutting individual chunks of cheese from a slab without any routine manual labor involved in separating the individual cut chunks from the slab.
It is another object to provide cutting harp apparatus which cuts the chunks both longitudinally and transversely while the slab travels a single straight line path, thus to be able to complete cutting the slab on a single straight conveyor.
It is yet another object to provide a single cutting harp which cuts the slab both in the longitudinal direction of movement of the slab, and transversely across the slab, thus to cut and sever individual consumer-size chunks of cheese at a single work station.
It is yet another object to provide a method of controlling the mass of the chunks of cheese being cut by weighing respective ones of the cut chunks, reporting the recorded weights to a controller, and wherein the controller sends corrective instructions to the drive mechanism driving the cheese through the cutting harp, thus to adjust the distance by which the leading edge of the slab or slab remainder is pushed through the harp before the harp makes the transverse cuts which release the chunks from the slab.
It is still another object of the invention to provide a method of advancing the slab of cheese through the cutting harp by confining the slab between an underlying feed conveyor and an overlying conveyor, biasing one of the conveyors toward the other, and engaging and impressing protuberances on facing surfaces of the conveyors against the top and/or bottom surface of the cheese slab, without penetrating or otherwise fracturing the surface of the slab of cheese, and then driving the conveyors to thus drive sequential slabs of cheese through the harp without having to retract pushing apparatus.
In a first family of embodiments, the invention comprehends a cutter for cutting slabs of food product such as cheese into smaller chunks. The cutter comprises a feed conveyor having an intake end and a discharge end, and a conveying surface for conveying a such slab of food product thereon; slab drive apparatus for driving a slab of such food product along the feed conveyor from the intake end toward the discharge end; and a cutting harp disposed adjacent the discharge end of the feed conveyor. The cutting harp comprises a frame, a central opening inside the frame, and a plurality of cutting devices, such as cutting wires, operative to make cuts extending through the food product and across the opening from adjacent respective ones of the cutting devices. The opening is aligned with the feed conveyor such that a slab being discharged from the feed conveyor passes through the opening and such that, when such slab of food product is driven through the opening in the harp, the cutting devices effect cuts in such food product in the direction of advance of such slab of food product. The invention further comprises transverse harp drive apparatus, for driving the harp in a direction transverse to the direction of advance of the slab for severing chunks of the food product from the slab.
In preferred embodiments, the cutter is a cheese cutter.
The cutter preferably includes hold-down apparatus, such as a hold-down bar or a hold-down roller, mounted for reciprocal movement into and out of engagement with the slab of food product, adjacent the cutting harp for holding the food product against the feed conveyor while the harp is being driven in the transverse direction for severing the chunks of food product from such slab.
Preferably, the cutter apparatus preferably includes a take-away conveyor taking the severed chunks away from the cutting harp, and further includes a weighing device for weighing such chunks, and a controller receiving weight readings from the weighing device, and sending adjustment instructions to the slab drive apparatus to thereby adjust subsequent incremental predetermined distances.
In some embodiments, the invention includes a breaker bar downstream of and adjacent the harp for engaging top surfaces of the severed chunks and urging the chunks downwardly from the harp.
In preferred embodiments, the slab drive apparatus comprises the feed conveyor providing underlying support of the slab of food product at a feed conveyor support surface, and an overlying conveyor extending along the feed conveyor in facing relationship with the feed conveyor, for interfacing with the slab of food product at an overlying conveyance surface, a conveyance cavity thus being defined between the feed conveyor support surface and the overlying conveyor conveyance surface, the feed conveyor and the overlying conveyor being cooperatively driven at a common speed. At least one of the feed conveyor and the overlying conveyor is biased against the other of the feed conveyor and the overlying conveyor through the slab of food product, for advancing the slab of food product toward the cutting harp.
In some embodiments, at least one of the support surface and the conveyance surface, optionally both the support surface and the conveyance surface, comprise protrusions spaced about the respective surface for engaging the slab of food product and thereby assisting in advancing the slab of food product through the harp.
In preferred embodiments, the cutting wires on the harp are mounted to the frame by eccentric mounting wheels whereby the cutting wires can be moved transversely of a path of advance of the slab of food product by rotating respective ones of the mounting wheels.
In a second family of embodiments, the invention comprehends a method of controlling weight of chunks of food product cut from slabs of such food product. The method comprises, using slab driving apparatus, advancing a slab of a selected food product a predetermined first drive distance through a cutting harp comprising cutting devices such as cutting wires, and making longitudinal cuts of at least first predetermined lengths in the slab of food product. The method further includes, after making the cuts of first predetermined lengths, moving the harp transversely across the slab and thereby severing respective chunks of the food product from the slab. The method yet further includes weighing the chunks of food product so severed from the slab, and in a controller, comparing measured chunk weight against a predetermined desired chunk weight, determining an adjustment to the first predetermined distance, and sending a signal from the controller to the slab drive apparatus thereby adjusting the drive distance, and correspondingly adjusting the sizes of subsequently-cut chunks of the food product.
In some embodiments, the method includes stopping advance of the slab before moving the harp transversely to sever the chunks.
In preferred embodiments, the method includes advancing the slab of food product on a conveyor, and exerting a force holding the food product slab against the conveyor adjacent the harp while moving the harp transversely across the slab and severing the respective chunks from the slab.
In some embodiments, the method includes making the longitudinal cuts with a first cutting harp, and making the transverse cuts, which sever the chunks from the slab, with a second cutting harp.
Further to preferred embodiments, the method includes adjusting spacing between the cutting wires of the harp by rotating eccentric mounting wheels mounting the cutting wires to the harp frame, thus to move the cutting wires transversely of a path of advance of the slab, and thereby to adjust the distance between respective ones of the wires.
In a third family of embodiments, the invention comprehends a method of advancing a slab of cheese into and through a cutting harp, and thereby cutting the slab of cheese. The method comprises positioning the slab of cheese between a first underlying conveyor having a support surface, and a second overlying conveyor having a conveyance surface, wherein at least one of the first and second conveyors is biased against the other of the first and second conveyors through the slab of cheese. At least one of the first and second conveyors bears protrusions spaced about the respective surface and urged into a corresponding surface of the slab of cheese. The method further includes driving the first and second conveyors such that the protrusions, in combination with friction forces of the support surface and the conveyance surface, drive the slab of cheese into and through the cutting harp, thereby cutting the slab of cheese.
The method includes, in addition to making longitudinal cuts by advancing the cheese through the harp, moving the harp transversely across the slab and thereby severing respective chunks of cheese from the slab.
In preferred embodiments, both of the first and second conveyors bear protrusions spaced about the respective support surface and the conveyance surface such that protrusions on both of the first and second conveyors participate in driving the slab of cheese into and through the cutting harp.
In some embodiments, the method includes, on an ongoing basis, biasing a hold-down roller against a top surface of the slab of cheese between the overlying conveyor and the harp and thereby stabilizing the slab of cheese against substantial transverse movement while moving the harp transversely across the slab to thereby cut the cheese.
In some embodiments, the method includes intermittently biasing a hold-down bar against a top surface of the slab of cheese between the overlying conveyor and the harp and thereby stabilizing the slab of cheese against substantial transverse movement while moving the harp transversely across the slab.